While the book is not about audio, a fascinating read is Dr. Cordelia Fine's "A Mind of Its Own: How Your Brain Distorts and Deceives". It explains how our brain works and how easily it is swayed by subjectivities, both conscious and subconscious. Audiophiles don't become immune to this human trait simply because the subject is audio equipment.
But, if you've got the money and something makes you happy, go for it! Just don't expect that everyone else is going to buy in.

